Ink distributing means in endless screen printing machines

ABSTRACT

A continuous printer including a framework supporting an endless platen and means to move material onto the platen for movement therewith. Printing means comprising an endless stencil screen mounted on spaced rolls are disposed adjacent to one run of the platen for printing the material and includes ink distributing means. The ink distributing means includes a housing removably supported on the framework and defining a substantially enclosed ink cavity disposed about an applicator roller journalled in the housing. A table supports the run of the platen opposite the printing means and a friction band of a material of a lower surface friction coefficient than that of the material of the platen is disposed between the runs of the platen and has a run which extends between the platen and the table and is movable with the platen for reducing friction between the platen and the table. Toothed means are provided for movement with the platen and mesh with toothed means on the screen supporting rollers to drive the rollers and to insure continued registration between the stencil screen and the material to be printed.

United States Patent Vasilantone 1 1 3,688,692 51 Sept. 5, 1972 [54] INKDISTRIBUTING MEANS ENDLESS SCREEN PRINTING MACHINES [72] Inventor:Michael Vasilantone, 147 E. 1st

Ave., Roselle, NJ. 07203 221 Filed: May 14,1970

21 App1.No.: 37,113

52 U.S.Cl. ..101/122,'101/119,101/123, 101/115 [51] 1m.c1....;..B41l13/08,B41f10/26 [58] Field of Search ..l01/116,114,119,120, 121,101/122, 115, 123, 364,349, 348, 367, 314

[56] References Cited UNITED STATES PATENTSv 220,547 10/1879Prouty'.....' ..101/364 1,079,339 11/1913 Henriessey ..101/348 1,421,8847/1922 Yohns ..101/l22 2,276,181 3/1942 Foster ..101/116 2,320,269 5/1943 Darenberg et a1 101/ 1 22 2,397,853 4/1946 Gist ..1 18/261 X2,419,695 4/1947 Shuttleworth et al. 101/1 19 2,429,442 10/1947Worthington 1 01/ 350 2,887,044 5/1959 Smejda ..101/1l5 2,963,964 12/1960 Klump 101/ 123 3,102,469 9/1963 Sherman. 101/122 Primary Examiner-William B. Penn Attorney-John J. Byme [57] ABSTRACT A continuousprinter including a framework support- ,ing an endless platen and meansto move material onto the platen for movement therewith. Printing meanscomprising an endless stencil screen mounted on spacedrolls are disposedadjacent to one run of the platen for printing the material and includesink dis-- tributing means. The ink distributing means includes a housingremovably supported on the framework and defining a substantiallyenclosed ink cavity disposed about an applicator roller joumalled in thehousing; A table supports the run of the platen opposite the printingmeans and a friction band of a material of a lower surface frictioncoefficient than that of the material of the platen is disposed betweenthe runs of the platen and has a run which extends between the platenand "the table andismovable with the platen for reducing, .frictionbetween the platen and the table. Toothed means are provided formovement with the platen and mesh with toothed means on the screensupporting rollers to drive the rollers and to insure continuedregistration between the stencil screen and the material to be printed.

10 Claims, 6 Drawing Figures ously printing a web of material ofindeterminate length.

This invention is an improvement over the continuous printing machinedisclosed in my U.S. Pat. No. 3,468,247, issued Sept. 23, 1969,entitled: CONTINU OUS PRINTER WITH MEANS TO MAINTAIN A MOVING WEBLATERALLY TAUT. Generally, that patent discloses dual, vertically spacedendless platens with printing means disposed therebetween for printingon two oppositely moving flexible webs simultaneously, and isparticularly directed toward means for laterally stretching the flexiblematerial taut on its respective platen. Such means include an endlesslocking strip on each side of each platen and movable therewith whichstrip stretches the material taut on the platen by clamping overlappingedges of the material against the vertical side edges of the respectiveplatens.

In many prior art printing machines, not necessarily continuous printersof the type with which this application is concerned, using rollerink-applicators, the roller is substantially entirely exposed to theatmosphere such that the ink applied thereto tends to dry up and cake onthe roller after a period of time. This problem has become magnified bythe increasing use of inks which dry very rapidly upon exposure to theatmosphere. It is highly desirable to maintain these quick-drying inksfree from exposure to the atmosphere until the last possible moment.Additionally, inks give off fumes or odors which are highly irritatingto the eyes and the skin of close-by workers and are otherwise adangerous source of pollution for the working atmosphere.

Another problem in prior art continuous stencil printing machine is theslippage or gradual loss of'registration between the stencil screen ofthe. printing means and the material to be printed. Generally, therollers and stencil screen are driven by friction, both by the platenand, as in my above-mentioned patent, by the locking strip. In frictiondrive systems nothing is provided to positively maintain properregistration between the screen and the platen and consequently thematerial on the platen. This problem becomes particularly acute insituations where a plurality of stencil printing means are used forprinting different portions of the same pattern on a particular run ofmaterial. Minute variations in sizes of the stencil supporting rollers,for example, are magnified after extended periods of time and theprinting means will not be in complete registration with the previouslyprinted portions of the material.

Another difficulty in continuous printers especially of the endlessplaten type is the friction encountered by the rubberlike heavy platenagainst its supporting table. Generally a supporting table must beemployed on the underside of the platen opposite the printing station.The friction between the rather heavy belt and the table creates asubstantial load on the drive means for the platen. Additionally, guiderails are generally employed along the side edges of the platenincreasing the frictional forces and thereby creating an additional loadon the platen belt drive motor.

It is an object of this invention to overcome the above-mentionedproblems in continuous stencil printing machines. r

More specifically, it is an object of this invention to provide an inkdistributing assembly which includes a housing surrounding an applicatorroller which housing defines an enclosed ink cavity and whichsubstantially protects the ink from exposure to the atmosphere untilapplication to the stencil.

It is another object of this invention to provide means forrecirculating the excess ink from the applicator roller during eachrevolution and after it has been momentarily exposed to the atmosphere..The recirculated ink is mixed with fresh ink within the cavity definedby the housing.

It is another object of this invention to assure proper registration ofthe rollers upon'which the stencils-are mounted by providing cooperatinggear means between the moving platen and the stencil supporting rollersinsuring registration between the print means and the platen andconsequently the material to be printed. I

It is another object of this inventionto reduce the frictional forcesbetween the platen and the supporting table by providing a friction bandhaving a surface friction coefficient considerably less that that of theplaten material and being positioned between the platen and itssupporting table and being movable with the platen. It is another objectof this invention to use similar friction bands to reduce friction alongthe side-edges of the locking strips which engage and move with theplaten.

It is a further object of this invention to provide a roller having aparticular surface configuration for a more uniform application of inkto the stencil. It is to be understood that in stencil printing thescreen is flooded with ink prior to being imprinted by a squeeze. Thesqueeze actually does the printing while the applicator roller regulatesthe amount of ink feed to the flood area and recirculates the excessink. More specifically, the applicator roller has a corrugated surface,the corrugations being in planes transverse to the longitudinal axis ofthe roller. The corrugated surface better retains the ink the rollerpicks up from the cavity, thereby insuring a more even distribution ofink. Adjustable doctor blades having edge configurations to mate withthe corrugated surface are positioned about the roller. One doctor bladelimits the amount of ink transferred by the roller to the stencil, whileanother removes excess ink from the roller after it contacts the stencilfor remixing with fresh ink in the ink cavity.

More particularly this invention includes an apparatus for continuouslyprinting insignia on a moving flexible material comprising a frameworkand a moving platen on the framework for receiving the material to beprinted. Means are provided for moving the material onto the platen formovement with the platen. Locking strips run with the platen and clampoverlapping edges of the material against the vertical side of theplaten. Stencil printing means are provided having one side adjacent toand movable with the flexible material on the platen and include an inkdistributing assembly mounted on the framework adjacent tothe other sideof the stencil printing screen for forcing ink through the screen ontothe material. The assembly includes a housing having a top and front andrear sides and being open at its bottom side adjacent to the other sideof the stencil printing screen and extending across the screen. Endplates are provided on the housing whereby the housing defines asubstantially enclosed ink cavity about the applicator roller.

The roller applicator is joumalled in the housing extending across theopen side of the housing for rolling engagement with the stencilprinting screen. Squeegee means are attached to the rear side of thehousing and extend downwardly into contact with the screen.

In an embodiment of the invention, a second platen is provided and asecond ink distributing assembly is provided for the second platen. Thesecond platen is vertically spaced above the first platen and sandwichesthe stencil printing means therebetween. Support tables support thatportion of the platen runs which are opposite the printing means andendless friction bands are provided within the confines of the endlessplatens, each having a run which extends between the supporting tableand the platen for purposes of reducing friction therebetween. Similarfriction bands are provided along theside edges of the locking strip toreduce friction drag.

These and otherobjects of the invention will become more apparenttothose skilled in the art by reference to the following detaileddescription when viewed in light of the accompanying drawings wherein: 4

FIG. 1 is a side view in elevation'of the printing apparatus of thisinvention;

FIG. 2 is a side view in elevation of the printing unit of thisinvention;

FIG. 3 is a perspective view of a portion of the printing apparatus ofthis invention;

FIG. 4 is an enlargement of the portion encircled in FIG. 2 in crosssection;

FIG. 5 is a fragmentary cross-sectional view taken along lines 5--5 ofFIG. 4; and

FIG. 6 is a fragmentary rear view of the ink distributing assembly ofthis invention.

Referring now to the drawings wherein like numerals indicate like parts,the numeral 10 generally indicates the printing apparatus supported atits ends by legs 12 and along its middle by vertical uprights 14. Theprinting apparatus generally comprises three levels of endless belt-typeassemblies with platen belt assembly 16 at the lowest elevation, alocking strip assembly 18 at the intermediate elevation, and a secondplaten belt assembly or upper platen belt assembly 20 at the highestelevation. The assemblies l6, l8 and 20 are driven by motor 22 throughendless drive belts, chains or the like 23. The upper and lower endlessplatens 16 and 20 both move in a clockwise direction such that theirupper and lower runs respectively cooperate with the opposite runs ofthe counterclockwise driven endless locking strip 18 to thereby conveytwo separate webs of textile material 24 and 26 in opposite directionstherebetween.

The lower platen assembly 16 comprises endless platen belt 28 consistingof a web of hard, flexible material such as rubber or plastic isdisposed about rollers 30 and 32. The rollers 30 and 32 are rotatablysecured in the legs 12 and are spaced far enough apart so that the runof the platen is longer than the run of the locking strip assembly 18.Between the rollers 30 and 32, the lower run of the platen 28 issupported by rollers 34 which are mounted on'the uprights 14. Inwardlyfacing channels or side guide rails 36 are rigidly secured to theuprights l4 opposite the upper run of the platen 28. a

As best seen in FIG. 2, the side rails have a vertical web 38 providedwith a flange or skirt 40 on its upper end and a flange 42 wider thansaid skirt on its lower end. This guide rail is connected to table 46which table supports the run of the platen opposite the printing means.

The upper assembly 20 is identical to the lower assembly 16 except thatis is positioned so that its lower run cooperates with the locking stripassembly 18. In other words, it is the mirror image of the lowerassembly. The assembly includes a platen web 28' disposed around rollers30' and 32', a pair of side rails 36' and a table 46. The intermediaterollers 50 rotatably mounted on the uprights 14 support the upper run ofthe web 28'.

Heaters 31 and 33 can be disposed at each end of the printing apparatusas desired for purposes of drying the newly printed webs 26 and 24respectively. Each of the webs 24 and 26 are provided with takeup rolls35 and 35 and feed rolls 37 and 37' respectively.

The locking strip assembly 18 is'comprised generally of a parallel pairof endless locking strips 52 of resilient rubber-like material whichpasses over the opposite peripheral edges of end rollers 54 and 56 and aseries of four twin drum printing units 58. The operation of the lockingstrip is fully described in my above-mentioned US. Pat. No. 3,468,247,issued Sept. 24, I969. Generally, with reference to FIG. 3, the upperand lower runs of the lock strip 52 are housed within the guide rails 36and 36' and are urged against the vertical side edges of the respectiveplaten belts 28 and 28' by bearing means which will be described morefully below. It is to be noted that the platen runs are longer than thelocking strip runs and the webs 24 and 26 pass through a pair ofconventional tensioning rollers 108 and are received on the respectiveplaten webs 28 and 28'. The textile webs 24 and 26 are wider than theplaten belts and will therefore overhang the side edges somewhat.Consequently, since the locking strips normally tightly engage thevertical side edges of the respective platen runs, they will forcetheoverlapping portion of the textile webs downwardly over the side edgesof the respective platen belt tending to laterally stretch the materialand thereby clamping the overlapped portion between the locking stripand the vertical side edges of the platen.

Rollers 104 and 104' are joumalled on vertical axes at spaced pointsthroughout the length of the side guide rails 36 and 36. An endlessfriction band 106 passes around rollers mounted on vertical axes at eachend of the series of roller bearings 104 such that the endless bandsubstantially encompasses the bearings 104. The band 106 has an innerrun tightly engaging the respective locking strip and moving with saidlocking strip, and an outer run adjacent said side guide rail 36. Thefriction band is of a material such as stainless steel or of any othermaterial which has a surface friction coefficient substantially lessthan that of the rubber locking strip and thereby minimizing frictionalresistance between the locking belt and the bearing means. It is to beunderstood that as the respective platen moves through the apparatus,the locking strip is in substantially tight engagement with the sideedges of the adjacent platen runs and moves in unison with the platens.Therefore, the particular run of the platen, and the adjacent runs ofthe locking strip and friction band, moves as a unit through theprinting apparatus. The bearing means are identical on both sides of theprinting apparatus and on both the upper and lower platen assemblies.

Each drum printing unit is comprised of a pair of rotatable drums 62over which passes a continuous wire screen 64 preferably of stainlesssteel. Each screen 64 is suitably stenciled to provide the particularpattern desired. The stencils are attached to the rolls in a mannerconventional to those skilled in the art. The rollers 62 of eachprinting unit are spaced apart and are rotatably secured in a frameworkgenerally indicated by the numeral .68 which comprises boxlike endsupports 69 and 70 which are attached to the upper and lower side guiderails 36 and 36' respectively and extend around the tables 46 and 46'and the intermediate locking strip assembly 18. A crossbar 71 spans thevertical portions of the supports 69 and 70 on each side and, along withthe supports 69 and 70, rotatably supports the rollers 62.

An ink distributing assembly generally indicated by the numeral 74 isremovably attached to the printing apparatus by means of T-bar support76 which mates with fastening means 78. The support 76 is attached to abeam spanning the cross bars 71. The assembly comprises a housing 77having a roller applicator 79 journalled therein and extending acrossand partially through an opening in the lower side of the housing 77.The roller applicator consists of a surface which is corrugatedtransversely of the length of the roller. As best seen in FIG. 4,closing the rear side wall of the housing is a squeegee 80 of a suitablesemi-rigid material which is adapted to engage the screen stencil forpurposes of removing excess ink which may be deposited by the rollerapplicator 79. Wheels 84 are journalled 'in brackets mounted on thefront side of the housing and engage the stencil screen for purposes ofstabilizing the ink distributing assembly. Ink from a reservoir or othersuitable source which can be mounted on the printing apparatus or can belocated at a remote point is fed to a manifold 86 which extends thelength of the housing 77 which then extends transversely of the materialto be printed. Ink from the manifold chamber 86 enters the cavity 88defined by the housing 77 through tributary tubes 90.

A pivotally mounted doctor blade 92 extends the length of the rollerapplicator and includes a scalloped edge which engages and substantiallymates with the corrugated surface of the roller applicator 79. Thedoctor blade 92 has an adjusting knob 94 by which the doctor blade maybe pivoted toward and away from the roller to regulate the amount of inktransferred from the cavity 88 by the roller applicator 79 to thestencil screen surface 64. The corrugated surface of the rollersprovides a more even distribution of ink to the stencil to remove excessink not deposited on the stencil and cause it to recirculate and mixwith fresh ink in the cavity 88. For this purpose, a second doctor blade96 which is substantially identical to blade 92 is pivotally mounted atthe upper part of the cavity 88 in the housing 77. The doctor blade ispivotally adjustable by means of the knob 98 and removes excess ink notdeposited on the stencil screen. The rotational movement of the rollerapplicator causes the removed ink to flow in the direction of the arrowover the doctor blade 96 into the flow of fresh ink in the cavity 88.

End plates 99 enclose each end of the housing and each has-a resilientseal along its bottom edge maintaining the ink in the cavitysubstantially free from exposure to the atmosphere. The squeegee 82encloses one side, the ends plates seal each end, and the doctor blade92 and roller 79 substantially close off the under side of the cavity.The roller applicator 79 is substantially encompassed by the housing 77.This enclosed assembly localizes the ink and prevents ink from flowingto areas of the screen that cannot be scraped clean by the squeege. Itis to be understood that an identical ink distributing assembly 74' isused for the upper platen 28'.

Each locking strip 52 is provided with toothed gear means in theform ofa scalloped upper surface 53.

Each roller 62 has toothed gear means in the form of a scallopedperipheral edge 63 about each end thereof. During operation of thedevice, the scalloped portion 53 of the driven locking strip 52 matcheswith the sealloped portions of the rollers 62 to thereby drive therollers and, consequently, the stencil screen, at the same speed as thelocking strips and the upper and lower platens 28 and 28'. Prior artdevices relied upon friction contact between the rollers and the lockingstrips to drive the stencil screen. However, the provisions of thegearing arrangement as just described substantially insures absoluteprinting registration throughout the printing process.

In order to minimize the frictional contact between the platens andtheir respective supporting tables 46 and 46', endless friction bandsand 110' are disposed about rollers 112 and 114 and 112' and 114',respectively. The operation of the two friction bands is identical.Therefore, referring to the upper friction band 110', best seen in FIG.3, its lower run extends between the table 46 and the lower run of theplaten belt 28' and the upper run of the locking strip 52. Suitablelubricant is disposed between the surface and the friction band tominimize frictional contact therebetween. The table may be ribbedlongitudinally to further lessen frictional contact. It is to beunderstood that the friction band is of a material which has a lowersurface friction coefficient than that of the rubber-like platen. Inoperation, the friction band travels with the platen because of thegripping action of the rubber-like platen material, and since there islittle frictional resistance between the table and the friction band, aminimum load is placed on the drive motor 22.

In operation, webs 24 and 26- of material to be printed pass in oppositedirections in vertical spaced relationship through the printingapparatus 10 and are printed simultaneously by the stencil printingmeans 58 sandwiched between the upper and lower platen runs 16 and 20.Ink is distributed to the printing means by a substantially enclosedroller-applicator having a corrugated surface. It is to be understoodthat the ink is In -a general manner, while there has been disclosed aneffective and efficient embodiment of the invention,

limited to such an embodiment as there might be changes made in thearrangement, disposition, and form of the parts without departing from"the principle of the present invention as comprehended within the scopeof the accompanying claims.

I claim 1. An apparatus for continuously printinginsignia on a movingflexible material comprising, a framework, a moving platen onsaidframework for receiving said material to be printed,means for movingsaid platen in a continuous path, means formoving material onto itshould be well understood that theinventio'n is not 10 doctor. blademounted for ad ustable engagement Wlth' said platen for movement withsaid platen, stencil print:-

registration with said flexible material positioned on said platen, aunitary inkdistributing assembly through said screen onto said materialas it is moved therepast with said material, said assembly including asupport on said framework, a roller having a plurality of axially spacedink conveying annular grooves in the surface thereof joumalled in saidsupport and extending transversely of said platen and being in rollingengagement with said screen, means forming an ink receiving cavityhaving ink inlet means, a portion of the surface of said roller beingexposed to said cavity, an elongated squeegee on said support extendingparallel to said roller and spaced therefrom to define a screen floodingarea, said cavity and floodingarea being on opposite sides of saidroller, said squeegee member engaging said screen during screenmove-merit, and means cooperating with said grooved roller forregulating means having one'side adjacent to and movable: in

- mounted in a stationary manner on said framework adjacent to the otherside of said screen for forcingink' 8 ing the amount of ink passing fromsaid cavity tosaid flooding area through said grooves.

2. The apparatusof claim 1 wherein said ink assembly includes ahousingsubstantially enclosing said' cavity, roller and flooding area. 7

3. The apparatus of claim 1 wherein said regulating means is afirstdoctorblade mounted on said support for adjustable engegement with saidroller between'said cavity and said flooding area.

The apparatus of claim 3 and including a second the roller in an areapositionedbetween said, first doctorblade and said squeegee'for removingand recirculating excess ink from said roller-applicator after it haspassed through said flooding area and before it receives fresh ink insaid cavity. a

5-. The apparatus of claim 1 and including means for rernovablymount'ing said ink distribution assembly as a unit, said meanscomprising fastening means on said support for engagement with matingfastening means on said framework wherebysaid housing, squeegee, rollerand doctor means are supported in common by e. illi g of claim 4 whereinsaid first .and

second doctor blades have notched edges adjacent said roller surfacegenerally conforming to said grooved surface such that the portionsofsaid blades between said notches are ajdustably received in saidgrooves.

7. The apparatus of claim 1 wherein said stencil printing meanscomprises a pair of spaced apart rotatable drums, an endless screenmounted to pass around 10. The apparatus of claim 1 wherein said squeegeis I a flexible elongated blade.

t I t i

1. An apparatus for continuously printing insignia on a moving flexiblematerial comprising, a framework, a moving platen on said framework forreceiving said material to be printed, means for moving said platen in acontinuous path, means for moving said material onto said platen formovement with said platen, stencil printing means having one sideadjacent to and movable in registration with said flexible materialpositioned on said platen, a unitary ink distributing assembly mountedin a stationary manner on said framework adjacent to the other side ofsaid screen for forcing ink through said screen onto said material as itis moved therepast with said material, said assembly including a supporton said framework, a roller having a plurality of axially spaced inkconveying annular grooves in the surface thereof journalled in saidsupport and extending transversely of said platen and being in rollingengagement with said screen, means forming an ink receiving cavityhaving ink inlet means, a portion of the surface of said roller beingexposed to said cavity, an elongated squeegee on said support extendingparallel to said roller and spaced therefrom to define a screen floodingarea, said cavity and flooding area being on opposite sides of saidroller, said squeegee member engaging said screen during screenmove-ment, and means cooperating with said grooved roller for regulatingthe amount of ink passing from said cavity to said flooding area throughsaid grooves.
 2. The apparatus of claim 1 wherein said ink assemblyincludes a housing substantially enclosing said cavity, roller andflooding area.
 3. The apparatus of claim 1 wherein said regulating meansis a first doctor blade mounted on said support for adjustableengegement with said roller between said cavity and said flooding area.4. The apparatus of claim 3 and including a second doctor blade mountedfor adjustable engagement with the roller in an area positioned betweensaid first doctor blade and said squeegee for removing and recirculatingexcess ink from said roller-applicator after it has passed through saidflooding area and before it receives fresh ink in said cavity.
 5. Theapparatus of claim 1 and including means for removably mounting said inkdistribution assembly as a unit, said means comprising fastening meanson said support for engagement with mating fastening means on saidframework whereby said housing, squeegee, roller and doctor means aresupported in common by said fastening means.
 6. The apparatus of claim 4wherein said first and second doctor blades have notched edges adjacentsaid roller surface generally conforming to said grooved surface suchthat the portions of said blades between said notches are ajdustablyreceived in said grooves.
 7. The apparatus of claim 1 wherein saidstencil printing means comprises a pair of spaced apart rotatable drums,an endless screen mounted to pass around said pair of drums and said inkdistributing assembly is between said drums.
 8. The apparatus of claim 6wherein a second platen is disposed oppositely from said first platensandwiching said printing assembly therebetween and including a secondink distributing assembly.
 9. The apparatus of claim 1 and including anink source, remote from said assembly, and conduit means communicatingsaid ink source to said cavity.
 10. The apparatus of claim 1 whereinsaid squeege is a flexible elongated blade.